CARTHAGE, N.C. -- Investigators are looking into whether a gunman accused of killing eight people in a North Carolina nursing home may have targeted the facility because his estranged wife worked there, police said Monday.

Carthage Police Chief Chris McKenzie said the woman, who he did not name, worked at the nursing home. He said he believed that the couple were recently separated but that he did not have any other details. He was not sure if the woman was at the nursing home at the time of the shootings.

Authorities said Robert Stewart, 45, went on a terrifying rampage in the Pinelake Health and Rehab center on Sunday morning, killing seven residents and a nurse and wounding three others.

"We're certainly looking into the fact that it may be domestic-related," McKenzie told The Associated Press ahead of a Monday morning news conference in this small town about 60 miles southwest of Raleigh in North Carolina's Sandhills region.

An ex-wife of Stewart's, Sue Griffin, told reporters Sunday she had not had contact with him since they divorced in 2001 but that he had "violent tendencies". Griffin added she didn't know how her ex-husband was connected to the nursing home or why he would shoot people there.

The injured included a police officer hailed as a hero for stopping the gunman by shooting and wounding him before more people could be killed.

Officials said the shooting could have been bloodier if 25-year-old Carthage Police Officer Justin Garner hadn't wounded Stewart while trading gunfire in a hallway. Garner was wounded in the leg.

"He acted in nothing short of a heroic way today, and but for his actions, we certainly could have had a worse tragedy," said Moore County District Attorney Maureen Krueger. "We had an officer, a well-trained officer, who performed his job the way he was supposed to and prevented this from getting even worse than it is now."

Griffin, Stewart's ex-wife, said Stewart had been recently reaching out to family members, telling them he had cancer and was preparing for a long trip and to "go away."

Griffin said she was married to Stewart for 15 years, and while they hadn't spoken since divorcing in 2001, he had been trying to reach her during the past week through her son, mother, sister and grandmother.

"He did have some violent tendencies from time to time," Griffin said. "I wouldn't put it past him. I hate to say it, but it is true."

Stewart was in custody, but authorities would not give any details about his injuries or treatment. He is charged with eight counts of first-degree murder and a charge of felony assault of a law enforcement officer.

Stewart was not a patient or an employee at the nursing home and wasn't believed to be related to any of the victims, authorities said.

Beverly McNeill said her mother, Pinelake resident Ellery Chisholm, called moments after the gunman stormed into her room and pointed his "deer gun" at her roommate. "They're up here shooting, they're up here shooting," Chisholm frantically told her 14-year-old granddaughter, Tavia, over the phone, McNeil said.

Chisholm told her daughter that she hid her face in her shirt so she couldn't see the man or what she expected him to do, McNeill said. He didn't shoot, but left the room and began shooting down the hallway.

The facility was closed after the attack as authorities worked to gather evidence inside and out. Krueger declined to say if authorities had moved the surviving residents from the 110-bed facility, including patients with Alzheimer's disease, saying only, "They're safe, which is the primary thing."

Among the items investigators found was a camouflaged-colored rifle or shotgun, which was leaning against the side of a Jeep Cherokee in the parking lot.

Sunday's rampage happened just weeks after a man killed 10 people, including his mother and several other relatives, in the worst mass shooting in Alabama's history on March 10. On March 11, a teen killed 12 people at his former high school in Germany.